Production and decay of sulfur excited species in an electron-cyclotron-resonance ion-source plasma

The most important processes for the creation of ${\text{S}}^{12+}$ to ${\text{S}}^{14+}$ ions excited states from the ground configurations of ${\text{S}}^{9+}$ to ${\text{S}}^{14+}$ ions in an electron cyclotron resonance ion source, leading to the emission of $K$ x-ray lines, are studied. Theoretical values for inner-shell excitation and ionization cross sections, including double-$KL$ and triple-$KLL$ ionizations, transition probabilities and energies for the de-excitation processes, are calculated in the framework of the multiconfiguration Dirac-Fock method. With reasonable assumptions about the electron energy distribution, a theoretical $K\ensuremath{\alpha}$ x-ray spectrum is obtained, which is compared to recent experimental data.